Control mechanism for gas and liquid storage apparatus



Aug. 8, 1939 .J. H. WIGGINS ET AL CONTROL MECHANISM FOR GAS AND LIQUIDSTORAGE APPARATUS Filed June 21, 1957 FlGi.

JOHN H. WIGGINS DONALD E. LARSON fid QM ATTORNEY Patented 8, 1939 QWiggim andnonald E. Larson, Chicago, 11]., asslgnors, bydlrect'and meansalignments,

of one-half to said Girleago Bridge it tion of Illinois Application June21,1981, Serial ua uam' 16 Claim.

This invention relates to control m for gas and/or liquid storageapparatus of the kind in which the gas space or vapor space of thestorage apparatus comprises a breather type root 5 or equivalent movablepart, that is adapted to move in opposite directions so as to vary thethe general type mentioned, which is of such design that the valveoperating apparatus is effectively protected from the weather and the Qvent valve is-so arranged that liquid cannot collect on the seat 01 sameand thus freeze the valve shut incold weather.

Other objects and desirable features of our invention will behereinafter pointed out. p a Figure 1 of the drawing is a verticaltransverse sectional view illustrating our improved control mechanismmounted in operative position on a storage tank equipped with a breathertype roof that is capable of moving vertically so as to vary the volumeof the gas space or vapor space of the tank.

Figure 2 is an enlarged vertical sectional view of said controlmechanism showing the vent valve in its open position so as -to permitair to enter the gas space of the tank to relieve an internal vacuum.

Figure 3 isa cross-sectional view of said con-.

trol mechanism illustrating how the vent valve is held tightly seatedwhen the roof of the tank moves upwardly due to an increase in theinternal pressure of the gas space; and

Figure 4 is a cross-sectional view of said control mechanism showing thevent valve opened so as to permit gases to escape from the tank torelieve the internal pressure of same.

The control mechanism herein illustrated is identical to the controlmechanism described in the Wiggins application for patent previouslyreferred to in that the operating mechanism for the venting meanscomprises a prime mover 0011-, sisting of a part carried by thevertically movable roof of the tank, and designed so that an internalpressure in the gas space causes said prime mover to move in onedirection and thus eflect a change in the position or condition of theventing means, and a partial vacuum or minus pressure in thegas spacecauses said prime mover to move in the opposite direction and thuseiiect a change in the position or condition of the venting means, butthe specific details of construction and ement of the prime mover andother parts of e valve operating mechanism of our improved controlmechanism are diflferent from that of the corresponding parts of theapparatus described in said Wiggins application. .In our improvedmechanism the prime mover consists of a member which forms a movablewall of a gas chamber inside of which is arranged parts that transmitmovement from said movable wall to a combined pressure relief and vacuumreliet vent valve to seat and unseat the same, said gas chamber beingconnected with the gas space or vapor space of the tank in such a waythat an internal pressure in the tank is capable of causing said movablewall or prime mover to move in one direction and an internal vacuum orminus pressure in the tank is capableof causing said movable wall orprime mover to move in the opposite direction. In such a controlmechanism the prime mover may be made only about one-half as large asthe prime mover of the apparatus described in the said Wigginsapplication without interfering with the emciency of the mechanism, andit has the added advantage of being of such design that snow is veryunlikely to collect and remain upon the parts that are used to operatethe vent valve and thus interfere with the successful operation of themechanism.

In the accompanying drawing, A designates the tank or container of thestorage apparatus which may be of any suitable or preferredconstruction, and B designates a movable member, for example, the roofof the tank A that forms the top wall of the gas space or vapor space,said roof being herein illustrated as consisting of a metal diaphragm'constructed and arranged so that it will rest upon and be supported byroof rafters C under certain conditions and is capable of movingupwardly into the position shown in broken lines in Figure 1, due to anincrease in the internal pressure in the container A asis common orusual in breather type and balloon type devices that are used forstoring gases and volatile liquids.

Our improved control mechanism comprises coacting parts which form agas-tight chamber x that is carried by and arranged in an elevatedposition on the vertically movable roof B of the container, a passageway3 for establishing communication between the chamber a: and the gasspace or vapor space of the container A, a combined pressure and vacuumrelief vent valve D for the gas chamber 1, and an operatingmechanism'for said vent valve that comprises a prime mover E constructedin the form of a domeshaped rigid member that forms a movable top wallfor the gas chamber at. The gas chamber a: is provided with a stationarybottom portion I iormed preferably by a metal plate supported bystandards 2 that project upwardly from a cover plate 3 attached to acircular collar 4 which surrounds an opening in the roof B of the tankthrough which air is admitted to said tank and through which gases canescape from said tank. The dome-shaped member E that forms the top wallof the gas chamber at is also made of metal and is mounted in such a waythat it is capable of moving relatively to the stationary bottom portionof the gas chamber. In the form of our invention herein illustrated, thedome-shaped member or prime mover E is pivotally connected at 5 to abracket i on the stationary bottom portion I of the gas chamber and isof greater diameter than said bottom portion, so that it is capable ofrocking vertically relatively to the same. A sealing element made ofgas-tight and flame-proof fabric F is attached to the lower edge of therim of the dome-shaped member E and to the peripheral edge of thestationary bottom portion I of the gas chamber, so as to produce andmaintain a gas-tight joint between said parts and still permit themember E, that constitutes the top of the gas chamber 3:, to rock on itspivot 5 when the pressure in the container A varies as hereinafterdescribed. The passageway 11 previously mentioned, that establishescommunication between the gas space of the container and the gas chamber1: of the control mechanism, may be formed either by an openendedtubular member I as shown in full lines in the drawing, or by a.conventional flame arrester la shown in broken lines in Figure 2,arranged in alignment with holes in the cover plate 3 and in the bottomportion I of the gas chamber.

The movements of the prime mover E are transmitted to the vent valve D.by a lever G pivotally mounted at I on a support 9 carried by ,thestationary bottom portion I of the gas chamber, one end of said leverbeing connected by a pivot II to an inwardly projecting lug on the rimof the dome-shaped member E and the opposite end portion of said leverbeing connected by a pivot II to a lug on the top side of the vent valveD. Said vent valve D is formed by a horizontally disposed valve elementthat is arranged above an annular valve seat I2 which surrounds acombined air inlet and gas outlet in the bottom portion I of the gaschamber and a weight I3 is mounted on the free end of the lever G so asto exert pressure on the same in a direction tending to hold the ventvalve closed' or seated. Preferably, a spring I4 is combined with thevent valve so as to prevent the same from chattering but said spring I4is not relied upon to hold the vent valve shut or in its closedposition. When the prime mover E rocks up wardly on its pivot I the freeend or weighted end of the lever G will move downwardly and thus forcethe vent valve towards its seat I2, and when said prime mover E rocks inthe opposite direction the lever G will lift the vent valve D or raiseit from its seat.

In addition to the parts just described, the valve operating mechanismcomprises a means that is used to open the vent valve D to providepressure relief. Said means preferably consists of a rod or equivalentdevice H projecting downwardly from the center of the prime mover E andprovided at its lower end with a trip device I 5 arranged so that duringthe upward move ment of the roof, 1B of the container A, saidtrip deviceIt comes in contact with a stationary part on the interior of thecontainer such, for example, as one or a pair of the roof supportingbeams C, with the result that If the roof B continues to move upwardlythe rod H will efiect a change in the position of the prime mover E andthe parts controlled or moved by said device. The rod H extendsvertically through a passageway 2, separate and distinct from thepassageway 1 through which air and gases flow into and out of thecontainer, and at the upper end of said rod H is an adjusting device Itthat may be manipulated to vary the effective length of the rod H or, inother words, vary the point in the upward movement of the roof B thatthe trip .device I5 comes into engagement with its coacting stationarypart or abutment on the interior of the container. A removable sealingcap I1 mounted on the dome-shaped cover E of the gas chamber preventsgases from escaping through a hole in the member E that receives theadjusting device It and a flame-proof packing I8 is mounted on the rod Hso as to maintain a tight joint between the same and the open-endedtubular member that forms the passageway z.

The operation of the apparatus above described is as follows:

As the roof B rises carrying with it the vent valve D and the operatingmechanism for said vent valve, the increase in pressure on the interiorof the container A will exert pressure on the prime mover E in such adirection as to rock said device upwardly on its pivot 5 and thus causethe lever G to hold the vent valve D tightly against its seat as shownin Figure 3. When the roof B reaches a certain approximate positionduring its upward movement, the stop device It contacts the pair of roofrafters C arranged in the path of travel of said stop device as shown inFigure 4 and thus arrests the upward movement of the rod H which dependsfrom the prime mover E. If the roof continues to move upwardly, theprime mover E will remain at rest due to the fact that the stop device I5 is then in engagement with its coacting roof beams C and the free endof the lever G will swing upwardly, thus causing the vent valve D toopen as shown in Figure 4 and permit gases to escape from the gaschamber 1:, thereby providing pressure relief for the container A. Aftersuch venting of the gas space of the container the roof B will start tomove downwardly and while said roof is descending, the vent valveremains in its closed pwition, the roof finally coming to rest on theroof rafters C as shown in full lines in Figure 1. If thereafter thepressure decreases and finally reaches a degree where a partial vacuumor minus pressure is set up in the gas space of the container and in thegas chamber :0, a downward force is exerted on the prime mover E whichcauses said device E to rock downwardly on its pivot C, thereby raisingthe'free end or weighted end of the lever G and causing the vent valve Dto open as shown in Figure 2 and permit air to enter the gas chamber a:and also the gas space of thecontainer so as to provide vacuum relief.

In a control mechanism of the construction above described, the partsare so compactly arranged that it is practicable-to make the prime moverIt not over five or six feet in diameter and still obtain a controlapparatus that is absolutely reliable in operation as there is verylittle liability of snow collecting and remaining upon the prime mover Ein suflicient quantities to interfere with the operation of same. Such avalve operating mechanism is easy to install; most of the parts of sameare positioned inside of a gas-tight chamber and are thus protected fromthe weather and the vent valve and its coacting seat are so constructedand arranged that it is impossible fora liquid to collect on the seat ofsaid valve and thus freeze it shut.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. A storage apparatus of the general kind described, comprising acontainer whose gas space is provided with a movable part that isadapted to move to vary the volume of saidgas space, a gas chambercarried by said movable part and provided with a prime mover formed by arockable part of said chamber that is capable of moving relatively tothe said movable part of said container, a hollow member for connectingsaid gas 'chamber with the gas space of the container, a venting meansfor said gas chamber, and apparatus positioned inside of said gaschamber and ,hollow member for actuating said venting means.

2. A storage apparatus of the general kind described, comprising acontainer whose gas space is provided with a movable part that isadapted to move to vary the volume of said gas space, a gas chambercarried by said movable part and arranged in communication with the gasspace of the container, a vent valve for said gas chamber arrangedinside of same, and an operating mechanism for said valve comprising aprime mover formed by a hinged wall of said gas chamber that is capableof moving relatively to the said mov- 1 able partmf said container.

3. A storage apparatus of the general kind described, comprising acontainer whose gas space is provided with a movable part that isadapted to move to vary the volume of said gas space, a gas chambercarried by said movable part and arranged in communication with the gasspace of the container, a vent valve for said chamber, and an operatingmechanism for said valve comprising a prime mover formed by arigid topwall for said chamber that is pivotally mounted and arranged so as to becapable of being moved relatively to the said movable part of thecontainer by the pressure in the gas space of the container.

4. A gas and/or liquid storage apparatus, comprising a containerprovided with a vertically movable roof, a gas chamber mounted on saidroof and arranged in communication with the gas space of the container,said gas chamber having a wall that is adapted to be moved in onedirection by a certain approximate positive pressure in the containerand to be moved in the opposite direction by a certain approximate minuspressure in the container, a vent valve for said gas chamber, and avalve operating means in said chamber for causing the movement of themovable wall of said gas chamber to effect a change in the condition orpositionof the vent valve.

5. A gas and/or liquid storage apparatus of the kind described in claim4, in which thevent valve is arranged on the interior of the gaschamber.

6. A gas and/or liquid storage apparatus of the kind described in claim4, provided with means for utilizing the bodily movement of the roof tocause the movable wall of the gas chamber to effect the unseating of the.vent valve to provide pressure relief.

'l. A gas and/or liquid storage apparatus of the kind described in claim4, in which the movable wall of the gas chamber is attached to a means"arranged so that during the upward movement of the roof said means willexert pressure on said movable wall in a manner to cause the same toeffect the unseatingof the vent valve to provide pressure relief.

8. A gas and/or liquid storage apparatus, comprising a containerprovided with a roof that is adapted to move upwardly and downwardly tovary the volume of the gas space of the container, a gas chamber mountedonthe top side of said roof and provided with a movable top wall, theinterior of said gas chamber communicating with the gas space of thecontainer, a vent valve, means inside of said gas chamber for utilizingthe movement of the top wall of said chamber in one direction to seatsaid valve and in the opposite direction to unseat said valve, and anoperating device depending from the movable top wall of the gas chamberand arranged to cooperate with a stationary part to cause said top wallto assume a position to eifect the unseating of said valve to providepressure relief when the roof rim is connected by a flexible sealingelement to a stationary portion. at the bottom of the' gas chamber. 7

' 11. A gas and/or liquid storage apparatus of the kind described inclaim 8, in which the means 50 inside of the gas chamber that isemployed to seat and unseat the vent valve consists of a lever pivotallymounted on a stationary part at the bottom of the gas chamber and havingone of its ends attached to the movable top wall of the gas chamber andits opposite end, attached to the vent valve. 7

12. A gas and/or liquid storage apparatus of the kind described in claim4, in which the movable wall of said gas chamber causes said vent valveto be held tightly seated during a portion of the upward movement of theroof.

13. A gas and/or liquid storage apparatus of the kind described in claim4, in which the movable wall of said gas chamber causes said vent valveto open to provide vacuum relief for the gas space of the containerunder certain conditions.

. 14. A gas and/or liquid storage apparatus of the kind described inclaim 4, in which the said approximate minus pressure in the containeris capable of causing the movable wall of the gas chamber to move in adirection to open the vent valve to provide vacuum relief when the roofof the container is in its extreme downwardly deflected condition. 16

15. A gas and/or liquid storage apparatus of 16. A gas and/or liquidstorage apparatus 01' the kind described in claim 4, in which the gasthe kind described in claim 4, in which the valve chamber is providedwith a stationary bottom operating means comprises a trip device in thegas part, the movable wall of said chamber is formed space of thecontainer, carried by a part that is by a hinged or pivoted part at thetop of said attachedtothe movablewallof said gas chamber. 5

chamber, and the vent valve is mounted on the JOHN H. WIGGINS.stationary bottom part of said chamber. DONALD E. LARSON.

